Immense Riches of the Birds' World (original) (raw)
Related papers
MultiMedia Publishing, 2006
Birds are among the most extensively studied of all animal groups. Hundreds of academic journals and thousands of scientists are devoted to bird research, while amateur enthusiasts (called birdwatchers or, more commonly, birders) probably number in the millions. Birds are categorised as a biological class, Aves. The earliest known species of this class is Archaeopteryx lithographica, from the Late Jurassic period. According to the most recent consensus, Aves and a sister group, the order Crocodilia, together form a group of unnamed rank, the Archosauria. Phylogenetically, Aves is usually defined as all descendants of the most recent common ancestor of modern birds (or of a specific modern bird species like Passer domesticus), and Archaeopteryx. Modern phylogenies place birds in the dinosaur clade Theropoda. Modern birds are divided into two superorders, the Paleognathae (mostly flightless birds like ostriches), and the wildly diverse Neognathae, containing all other birds.
The Auk, 2012
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.
Introduction: Studying Birds in Time and Space
Fascinating Life Sciences, 2018
Birds are of high public interest and of great value as indicators of the state of the environment. Some 11,000 species are a number relatively well to handle. From a scientific point of view, it is not easily answerable what a species is, since speciation and extinction are ongoing evolutionary processes and differentiation among species works on various traits. Contemporary systematics attempts to take into account as many criteria as possible to delimit species. The currently most influential approach is the use of genomic sequences, be it as a neutral marker or to discover the underpinnings of functional traits. The study of the outer appearance of birds nevertheless remains fundamental, since that is the interface between a bird and its biotic and abiotic environment. For the majority of bird species, acquired traits of vocal communication add to this complex. Birds can also vary the timing of important behavior such as breeding or molting. Most fascinating among circannual behavior are the long-distance movements that can quite fast evolve and have genetic bases. Despite such dispersal ability for many bird species, geographic barriers play a large role for distribution and speciation in birds. Extant, former, and potential future ranges of a species can be modeled based on the abiotic niches individuals of this species have. Within a species' range, genetic and phenotypic traits vary and promote to process toward species splits. Beside geographic frameworks, ecological circumstances play a major role and contribute to natural selection but also trigger individual responses such as phenotypic plasticity, modification of the environment, and habitat selection. Anthropogenic global impacts such as climate and land-use changes (e.g., urbanization) force extant species to accelerated modifications or population splits or let them vanish forever. Only if humans leave more room and time to birds and other organisms can we expect to maintain such a number of diverse bird species, although they will keep modifying, splitting, and becoming extinct-but for natural reasons.
Symposium: Ancestry and origin of birds
Journal of Ornithology, 1994
A skeletal model constructed from casts of the London Archaeopteryx gives a unique threedimensional look at a Jurassic bird. The acetabulum of the pelvis has the articular region restricted to the anterior margin. This is unlike modern birds where the articular area is posterior and supplemented by an antitrochanter; nor is it like dinosaurs that have their articular surface on the dorsal rim of the acetabulum. When the leg is articulated to the pelvis, the only posture possible is erect, and primate-like. A vertical posture along with elongated manus phalanges, highly recurved manus claws, and laterally facing glenoids provide an ideal morphology for climbing tree trunks. They also support suggestions that flight may have originated from vertical clinging and leaping. When on the ground, Archaeopteryx would have been clumsy and vulnerable to predators. Because of the lack of a triosseai pulley system it is unlikely that it could take off directly from the ground. This capacity is the signal feature of more modernized birds with a horizontal posture, antitrochanter, upward facing glenoid, keeled sternum, triosseal canal, loss of manal claws and phalanges.
Living dinosaurs: the evolutionary history of modern birds
2011
BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.